Laser processing apparatus and method using beam split

Abstract

Disclosed are a laser processing apparatus and method that can effectively remove a low-k material formed on a wafer. A laser processing apparatus of the invention is a laser processing apparatus that processes a subject on which a low-k material is formed. The laser processing apparatus includes a laser generating unit that emits a laser beam; and an optical system that splits the laser beam emitted from the laser generating unit into two and irradiates the split laser beams onto the subject In this case, the optical system includes a pair of condensing lenses in which cut surfaces that are cut at a predetermined distance from central axes to be parallel to the central axes contact with each other, and the interval between the two split laser beams is the same as the interval between two edges of the low-k material in a removal subject region. According to the invention, after splitting a laser beam into two laser beams and primarily removing the edges of the low-k material in the removal subject region using the laser beams, the remaining low-k material between the edges is removed. As a result, it is possible to improve processing quality.

Description

TECHNICAL FIELD[0001]The present invention relates to a laser processing apparatus and method, and more particularly, to a laser processing apparatus and method that are capable of effectively removing a low-k material that is formed on a wafer.RELATED ART[0002]In general, in a process of manufacturing a semiconductor element, a low-k material is used for pattern formation and insulation. However, since the low-k material has high viscosity, when a wafer is processed by a mechanical method in a subsequent process, the low-k material adheres to a saw, causing the saw to be worn and decreasing a processing speed. When the low-k material is processed, a lump of low-k material may be removed and a processing surface becomes dull. The low-k material in a region other than a removal subject region is also removed, which lowers productivity.[0003]In order to prevent this problem, a method has been studied in which the low-k material is preferentially removed using a laser before processing...

AI Technical Summary

Benefits of technology

The invention provides a laser processing apparatus and method using beam split to remove low-k material from a wafer. The technical effects include improving processing efficiency and speed by primarily removing the edges of the low-k material and minimizing resistance applied by the low-k material during a subsequent process.

Problems solved by technology

However, since the low-k material has high viscosity, when a wafer is processed by a mechanical method in a subsequent process, the low-k material adheres to a saw, causing the saw to be worn and decreasing a processing speed.

When the low-k material is processed, a lump of low-k material may be removed and a processing surface becomes dull.

The low-k material in a region other than a removal subject region is also removed, which lowers productivity.

A laser that can achieve a small value of M2 is considered to be expensive equipment having excellent beam quality.

However, a minimal focal distance that is capable of protecting the condensing lens from being contaminated at the time of processing is about 20 mm.

As a result, most of the laser beams do not process the silicon, but damages a transfer device.

Thus, the low-k material may show a different reaction according to a wavelength, a beam size, and processing parameter of the laser, and this difference may cause the deterioration in the processing quality.

Accordingly, in the case where the low-k material is removed using a laser beam, if the kind of wafer or a width of a processing portion changes, a condensing lens and an optical system should be changed, which is inconvenient for a user.

As such, even though the method has been studied in which the low-k material is removed by laser processing, the above-described problems cannot be resolved.

In this case, however, when a width of a mechanical saw for processing substrate material such as silicon that is the main portion of the processing material, that is, a width of a processing portion is large, mechanical processing should be repeated a plurality of times, which decreases the processing speed.

Therefore, the corresponding method is not effective.

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